Week 11 Flashcards
Puberty
Describes the physiological, morphological and behavioural changes as the gonads switch from infantile to adult forms
Physical changes- growth
Adolescent growth spurt: rapid increase in the individuals height (and weight) as a consequence of the action of gonadal sex steroids
Height gain during puberty (average): boys-28cm, girls 25cm
Time minimum growth velocity: girls 9-10. Boys 9-12
Peak height velocity girls: 12 boys:14.
Time of decreasing growth velocity (epiphyseal fusion)
Physical changes: secondary sexual characteristics
Girls:
-breast development: controlled by ovarian oestrogens
-pubic and axillary hair: controlled by ovarian and adrenal androgens
Boys:
-development of penis, scrotum and pubic hair growth
-enlargement of larynx and laryngeal muscles (voice deepening)
-increase body muscle mass: controlled by testicular (and adrenal) androgens
Tanner stages- boys
Stage 1:
-Prepubertal: no pubic hair
-Testicular length <2.5cm
-Testicular volume <3.0ml
Stage 2:
-sparse growth of slightly curly pubic hair, mainly based on of penis
-testes >3ml (>2.5cm in longest diameter)
-scrotum thinning and reddening
Stage 3:
-thicker curlier hair spread to mons pubis
-growth penis in width and length; further growth of testis
Stage 4:
-adult type hair, not yet spread to medial surface thighs
-penis enlarged further; testes larger, darker scrotal skin colour
Stage 5:
-adult type hair spread to medial surface thighs
-genitalia adult size and shape
Tanner stages girls
Stage 1:
-prepubertal: no pubic hair
-elevation of papilla only
Stage 2:
-sparse growth long straight or slightly curly minimally pigmented hair mainly on Labia
-breastbud noted/palpable ; enlargement of areola
stage 3:
-darker, coarser hair spreading over mons pubis
-further enlargement of breast and areola with no separation of contours
Stage 4:
-thick adult type hair not yet spread to medial surface thighs
-projection of areola and papilla to form secondary mound above level breast
Stage 5:
-hair adult type and distributed in classic inverse triangle
-adult contour breast with projection of papilla only
When does puberty start
Boys:
Testicular volume 4mls
97th centile: 10 years
3rd centile: 14 years
Adulthood: 20-25ml
Girls:
Breast stagen Tanner 2
97th centile: 9.2 years
3rd centile: 13.2 years
What is needed for puberty
Sex chromosomes XX/XY
Functioning hypothalamus
Functioning pituitary
End organ function (ovary/testes)
Responsiveness of tissues to hormone
Hormonal changes at puberty
Physical changes:
-controlled by gonadal sex steroids
-regulated by LH and FSH
Orchestration of puberty through GnRH pulse generator (hypothalamus) resulting in pulsatile LH and FSH secretion (pituitary) hypothalamo-pituitary-gonadal axis
Precocious puberty
Onset of secondary sexual characteristics before 8 years (girl), 9 years (boy)
Menarche before 9 years may lead to short stature
May be earlier in some ethnic groups eg African- Caribbean girls
May be concordant (follows normal sequence)- central gonadotrophin activation
Or discordant (eg pubic hair with small testes)- peripheral sex hormone production
Delayed puberty
Absence of secondary sexual characteristics by 13 years (girl), 14 years (boy)
Delayed puberty leads to reduced peak bone mass and osteoporosis
Central precocious puberty
Early activation of pulsatile GnRH regulator therefore early activation of gonadal sex hormone production and action
Incidence 1 in 5000 to 10000
Idiopathic CPP: up to 80% female, only 30% male
Peripheral precocious puberty
GnRH remains silent
Higher levels sex hormones
Derived from gonads or adrenal, or androgen secreting tumours
Adrenarche
Onset of adrenal androgen production due to development/maturation of the ZR
Takes several years until early adolescent where ZR is complete and this results in higher levels of adrenal androgen precursors
Clinical features:
-transient growth acceleration
-pubic/axillary hair
-oily skin, mild acne
-adult type body odor
Adrenarche does not equal pubarche
Onset of Adrenarche independent from regulation of central puberty
Idiopathic premature Adrenarche
Definition: increased adrenal androgen secretion (above sex and age specific reference range before 8 years in girls and 9 years in boys)
And clinical signs of androgen action: pubic/axillary hair, body odor, mild acne, oily skin
Exclude precocious puberty, enzyme defect, virilising tumours
GnRH (LHRH) test
The test: IV injection of 100mcg GnRH analogue with blood sampling for LH and FSH at baseline and 30’ and 60’ after
Central PP: stimulation pubertal range. Stimulated LH:FSH ratio>1
Peripheral PP: stimulation prepubertal range or suppression. Stimulated LH:FSH <1
Causes central precocious puberty GnRH dependent
Idiopathic precocious puberty
CNS tumours: optic glioma associated with NF1, hypothalamic astrocytoma
CNS disorders: developmental abnormalities, hypothalamic hamartoma, encephalitis, Brain abscess, hydrocephalus, myelomeningocele, arachnoid cyst, vascular lesion, cranial irradiation
Secondary central precocious puberty ie CAH
Psychosocial
Causes peripheral precocious puberty GnRH independent
Increased androgen secretion: congenial adrenal hyperplasia (21OHD, 11OHD), virilising neoplasm, leydig cell adenoma, familial male precocious puberty- testotoxicosis
Gonadotropin secreting tumours: chorioepitheliomas, germinoma, teratoma, hepatoma, choriocarcinoma
McCune-Albright syndrome
Ovarian cyst
Oestrogen secreting neoplasm
Hypothyroidism
Iatrogenic or exogenous sex hormones
Consequences of early puberty
Psychological problems may arise as a result of:
-pubertal levels of sex steroids resulting in adolescent behaviour
-altered self image
-child expected to behave at appropriate to height age
Growth:
-fixed amount of growth in puberty means that although the child may present with tall stature, growth will finish early and final height is restricted
Metabolic:
-increasing evidence that children with PP develop long term metabolic complications (glucose intolerance/ diabetes, cardiovascular etc)
Treatment gonadotrophin-dependent (central) PP
Long acting GNRH analogues
-ie decapeptyl :IM injection every 12-10 weeks
-cessation of FSH and LH secretion
No evidence of long term adverse affects
Only evidence of benefit for adult height if onset <6 years
Decision re who is treated is individual- ability to cope with physical and emotional changes of puberty
Usually discontinues when of pubertal age
Delayed puberty
Absence of secondary sexual characteristics by 13 girl 14 boy
First period after 15 years age
May also be pubertal failure “arrest” when puberty begins but fails to progress adequately
Forms gonadal failure
Primary failure: hypergonadotrophic, hypogonadism. Disinhibition negative feedback problem with sex steroid production
Secondary failure: disorder hypothalamus or pituitary, Low FSH and LH so low levels sex steroid HPG axis not activated. Hypogonadotrophic and hypogonadism
Classification central hypo and hypo
Central (both sexes)
Intact HPG axis:
-constitutional delay of growth and puberty >50%
-chronic disease, poor nutrition, psychosocial deprivation, steroid therapy, hypothyroidism
Impaired HPG axis:
-tumours adjacent to HP axis (cranio, optic glioma, germinoma)
-congenital abnormalities (hypopituitarism, septo-optic dysplasia)
-irradiation and trauma
-GnRH/LH/FSH deficiency (including Kallmann, prader-willi, Laurence-moon-bardet-biedl syndrome)
Classification peripheral primary gonadal failure
Male:
-bilateral testicular damage (cryptorchidism, torsion, haemochromatosis)
-syndromes associated with cryptorchidism (noonan, prader-willi, Laurence-moon-bardet-biedl syndrome)
Female:
-disorders of sex development (eg complete androgen insensitivity syndrome CAIS)
-toxic damage (thalasssaemia, galactoseamia)
Both sexes:
-gonadal dysgenesis (female;turner syndrome 45XO, male; Klinefelter syndrome 47XXY)
-irradiation/chemo
Possible investigations
First line:
-FBC, UE, TFT, LFT, ESR, ferritin, coeliac screen
-karyotype (turners, klinefelters)
-basal LH, FSH, oestradiol/testosterone
-bone age
Second line:
-LHRH test
-male HCG stimulation test
-female pelvis USS
-female ovarian antibodies
Treatment of delayed puberty
Boys: testosterone: usually sustanon 50 (-250)mg IM monthly, slowly up titrated
Girls: oestrogen: usually 17b-ethinyl-oestradiol transdermal patches (ie evorel 25) slowly up titrated starting with 1/4 patch 3 days on, 3 days off
Why is height important to review in childhood
Measurements of growth provide a sensitive indication of health in childhood
Important determinants of growth
Parental phenotype and genotype
Quality and duration pregnancy
Nutrition
Specific system and organ intregrity
Psycho-social environment
Growth promoting hormones and factors
Normal phases of human growth
4 phases:
-pre natal
-infancy
-childhood
-adolescence
Prenatal growth
Most dramatic period of growth
Most important factors affecting growth of fetus: maternal size and nutrition (placental function and maternal)
Key hormones in fetal growth
Insulin
IGF-II
IGF-I
Key influences on childhood growth
Emotional wellbeing
Genetic factors
Nutrition
Chronic illness
Influences on GH secretion
GH stimulation:
-exercise
-stress
-hypoglycaemia
-fasting
-high protein meals
-perinatal development
-puberty
GH suppression:
-hypothyroidism
-hyperglycaemia
-high carb meals
-glucocorticoid excess
-aging
Changes in proportions throughout growth
Newborns: larger head, smaller mandible, short neck, rounded chest, abdomen prominence, short limbs
As we age: head finished ini first few years , proportional size of trunk is reduced, leg growth increases
Adolescents more growth limbs relative to trunk
Short trunk dysplasia, short limb dysplasia
Short stature: rhizomelic, mesomelic, acromelic, asymmetry
Growth standards in uK
Normal range 2nd-98th centile
What do the centiles show
Optimum range of weights and heights
Describes the % expected to be below
Half children should be between 25-75 c
How to measure children under2
Measure length before 2
Length board or mat
Without nappy or footwear
How to measure children over 2
Rigid rule with T piece or stadiometer
Ensure heels, bottom, back, head, touching apparatus with eyes and ears 90 degrees
Don’t try to stretch up measure on expiration
Shoes removed
Auxology
Height; weight; BMI; height velocity; head circumference
Plot all available previous heights
Parental heights added to child’s growth chart and adjusted to child’s gender
Mid parental height for a girl: (father height cm-13cm and mothers height cm)/2
Mid parental height for a boy: (mothers height +13cm +fathers height)/2
Final adult height ~8.5cm within mid parental height
Does child look proportional
History
Birth History - Maternal disease & meds/alcohol/smoking ,Any abnormalities on scans , Gestation, Delivery, Birth Weight ?SGA (=<10th centile), SCBU
Past Medical History -Hospital admissions, Chronic illness ,Systems Review for undiagnosed systemic illness (cardiac, GI, renal, respiratory), Recurrent ear infections, Thyroid symptoms, CNS symptoms
Neonatal History -Feeding, Tone ,Hypoglycaemia , Prolonged Jaundice
When did you start worrying? Height only or also weight? Red Book
Pubertal History -Age of each stage
Drug History -Steroids, even if just creams or inhalers
Infancy -Weaning, Feeding, Reflux
Intake -Detailed dietary history
Family History -Country of origin, Consanguinity, Siblings’ growth & puberty, Parental heights & puberty, Anyone particularly short, Anyone with difficulty conceiving, Other endocrine and autoimmune disorders
Development & Behaviour
Social History -Type of school, School performance, ?Shortest in the class, Household, Social worker
Red book
The personal child health record also known as PCHR or red book is a national standard health and development record given to parents/carers at child’s birth
Examination
Dysmorphology- take time
Neurocutaneous features
Midline defects
Goitres (hashimotos thyroditis); features of hypothyroidism
Approximate pubertal assessment
Visual fields
Spine; skeletal deformities, rickets
Signs of neglect or abuse
Consider
Birth weight- SGA?
Height centile/HV
Is the child crossing centiles >2 years
Drugs
Other illnesses (or symptoms)
Additional features: dysmorphic features, proportions
Short stature and female-. Consider TS
When to investigate
Measure height of child
Height parents and determine mid parental cenitle
Compare child’s height centile with mid parental
Re measure child’s height after period of time
Calculate present growth velocity
Abnormally slow or rapid-> investigate further irrespective height
Normal-> pathology unlikely
Investigations
Height -2.5 SDS or worse; and/or HV<25th centile (4cm/yr); + dysmorphic features
and/or below target height and/or crossing in centiles
No dysmorphic features
FBC/U&Es/LFTs/Bone profile CRP/ESR Coeliac screen* (Total IgA) TFTs IGF-1 PRL
REFER
Relative short stature and dysmorphic features: FBC/U&Es/LFTs/Bo ne profile CRP/ESR Coeliac screen* (Total IgA) TFTs IGF-1 PRL
Refer
Short stature and female- karyotype
If SGA without catch up growth by age 4 below target height refer
Short stature with disproportions- refer +/- skeletal survey
Short stature
A length or height >2 SD below mean for age and gender
Idiopathic short stature
Constitutional delay of growth and puberty with normal height prediction
ISS with delayed bone ageing and tempo of puberty
ISS with normal bone ageing and tempo of puberty
ISS with familial component
ISS without familial component
Impact of illness
Short stature does not equal endocrine cause
Any chronic disease can lead to short stature
GI: coeliac, IBD
Cardio: congential heart disease
Renal disease
Haematologic: chronic severe anaemia
Pulmonary: cf, bronchopulmonary dysplasia
Chronic inflammation and infection
Drugs:
-steroids
-ADHD medication
-radiotherapy for cancer
Constitutional delay of growth and puberty CDGP
One of the most common causes of short stature
Diagnosis of exclusion
More common in boys M:F 7:1
Poor growth becomes more evident from age 9-11 onwards when rest peers have pubertal growth spurt
Delayed puberty (in boys >14 years)
Delayed bone age low/normal height velocity
Often CDGP in parents
Final adult height normal or only slightly below target height
If concerns about bullying, self esteem etc treat with testosterone
Tall stature
Height >2 SDs above population standard
Above target height
Primary, secondary( [precocious puberty, pituitary gigantism, hyperthyroidis), idiopathic
Most tall children will be healthy
Things to consider especially in tall stature
Birthweight and length
Neonatal history- hypoglycaemia, abdominal wall defects
Developmental history
FH: 1 parent >2 SDs, history of cardiac/eye abnormalities
Thyroid status
Physical findings: obesity, disproportion (arms span), head circumference, arachnodactyly, cryptorchidism,
Growth chart- timing
Investigations tall stature
Endocrine
Imaging
Genetics
Overgrowth
With impaired final height:
-precocious puberty
-congenital adrenal hyperplasia
-mccune Albright syndrome
-hyperthyroidism
With increased final height:
-androgen or oestrogen deficiency
-oestrogen resistance
-pituitary gigantism GH excess
-Klinefelter
-Marfan syndrome
-homocystinuria
With Normal adult height:
-beckwidth-weidemann syndrome
-sotos syndrome
